Okay, second round (since I made the rules for this I get to amend them):
1) The "
Foundation" series by Isaac Asimov (which thanks to the later books would also get to include the robot stories involving R. Daneel Olivaw) This would seem difficult to make into a movie since so much of the plot involves so little action but actually I think that it would condense into a movie length plot easier for that reason.
2) "
The Empire of the East" by Fred Saberhagen (which gets to include the subsequent "
Books of Swords" series). And, face it, the
Beserker series was already done what with the "Terminator" franchise (although Harlan Ellison also claims to have had the original idea from which the movie was conceived, i.e. plagiarized) the only difference being the time travel element. Anyway, this is a fantasy series with its origin roots in science and technology...magic becomes reality through the use of a doomsday type machine in the distant past but remnants of technology still exist and still work.
3) "
Pandora's Star/Judas Unchained" (The Commonwealth Saga) by Peter F. Hamilton. This is a
sweeping sci-fi space opera that has it all. Two books, over 1500 pages with Dyson spheres and the best Mr. Spock-type character ever in the form of a female police detective. Seriously, you need to read this one and it should be made into a movie.
And about "Ringworld"...for Pete's sake, stop whining. I know that I took the best one but look at
all of the other Niven material I left you. And what about Pournelle and Niven/Pournelle? Come on. (I met Niven once. Nice guy. Signed all of my hardcovers including "The Integral Trees" and "Ringworld Engineers" I met Donaldson, too, and have signed first editions.)